The present invention relates to voltage sensing circuitry, and more particularly to threshold window circuits which determine whether a measured voltage lies within a given voltage range.
Window comparator circuits have long been used in various electronic industries to determine whether a measured parameter is within a window bound by upper or lower limits. One particularly useful application for window sensing is in voltage sensing circuits which determine if a voltage between two nodes is within a window. Typical circuits of this type generate a signal when a measured voltage is within the window.
One well-known voltage window sensing circuit includes, among other circuitry, two comparators, two voltage dividers (e.g., four resistors) and an output pull-up resistor. Unfortunately, while being sufficiently accurate, a large parts count renders these types of comparators relatively expensive and requires significant printed circuit board space. For these reasons, when costs and circuit board space need to be minimized, comparators of this well-known type are unsatisfactory.
As is evident from the foregoing, a need exists for a cost-effective, space-minimizing voltage-window sensing circuit capable of preserving the functionality of the common window comparator circuit at a relatively low cost and which requires minimal circuit board space.